Touch sensing type display device

ABSTRACT

A touch sensing type liquid crystal display device includes an array substrate includes a first substrate, a common electrode, a pixel electrode, and a touch sensing unit; a color filter substrate including a second substrate and facing the array substrate; an anti-static layer on an outer side of the second substrate and including an organic material and a carbon nano-tube; and a liquid crystal layer between the first substrate and an inner side of the second substrate.

This application is a continuation of co-pending U.S. patent applicationSer. No. 16/808,169, filed Mar. 3, 2020, which is a continuation of U.S.patent application Ser. No. 15/640,008, filed Jun. 30, 2017, now U.S.Pat. No. 10,620,729, which is a continuation of U.S. patent applicationSer. No. 15/287,426, filed Oct. 6, 2016, now U.S. Pat. No. 9,727,158,which is a continuation of U.S. patent application Ser. No. 13/051,000,filed Mar. 18, 2011, now U.S. Pat. No. 9,600,109, which claims priorityto Korean Patent Application No. 10-2010-0024914, filed on Mar. 19,2010. All of the above patent applications are hereby incorporated byreference for all purposes as if fully set forth herein.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to a liquid crystal display (LCD) device,and more particularly, to a touch sensing type liquid crystal displaydevice including an anti-static layer and a method of fabricating thesame.

Discussion of the Related Art

Recently, the LCD device has been widely used as a technology-intensiveand value-added device of next generation due to its low powerconsumption and portability. In general, the LCD device uses the opticalanisotropy and polarization properties of liquid crystal molecules toproduce an image. Due to the optical anisotropy of the liquid crystalmolecules, refraction of light incident onto the liquid crystalmolecules depends upon the alignment direction of the liquid crystalmolecules. The liquid crystal molecules have long thin shapes that canbe aligned along specific directions. The alignment direction of theliquid crystal molecules can be controlled by applying an electricfield. Accordingly, the alignment of the liquid crystal moleculeschanges in accordance with the direction of the applied electric fieldand the light is refracted along the alignment direction of the liquidcrystal molecules due to the optical anisotropy, thereby imagesdisplayed.

Since the LCD device including a thin film transistor (TFT) as aswitching element, referred to as an active matrix LCD (AM-LCD) device,has excellent characteristics of high resolution and displaying movingimages, the AM-LCD device has been widely used.

The AM-LCD device includes an array substrate, a color filter substrateand a liquid crystal layer interposed therebetween. The array substratemay include a pixel electrode and the TFT, and the color filtersubstrate may include a color filter layer and a common electrode. TheAM-LCD device is driven by an electric field between the pixel electrodeand the common electrode to have excellent properties of transmittanceand aperture ratio. However, since the AM-LCD device uses a verticalelectric field, the AM-LCD device has a bad viewing angle.

An in-plane switching (IPS) mode LCD device or a fringe field switching(FFS) mode LCD device may be used to resolve the above-mentionedlimitations. FIG. 1 is a cross-sectional view of an IPS mode LCD deviceaccording to the related art. As shown in FIG. 1 , the array substrateand the color filter substrate are separated and face each other. Thearray substrate includes a first substrate 10, a common electrode 17 anda pixel electrode 30. Though not shown, the array substrate may includea TFT, a gate line, a data line, and so on. The color filter substrateincludes a second substrate 9, a color filter layer (not shown), and soon. A liquid crystal layer 11 is interposed between the first substrate10 and the second substrate 9. Since the common electrode 17 and thepixel electrode 30 are formed on the first substrate 10 on the samelevel, a horizontal electric field “L” is generated between the commonand pixel electrodes 17 and 30. The liquid crystal molecules of theliquid crystal layer 11 are driven by a horizontal electric field suchthat the IPS mode LCD device has a wide viewing angle.

FIGS. 2A and 2B are cross-sectional views showing turned on/offconditions of an IPS mode LCD device according to the related art. Asshown in FIG. 2A, when the voltage is applied to the IPS mode LCDdevice, liquid crystal molecules 11 a above the common electrode 17 andthe pixel electrode 30 are unchanged. But, liquid crystal molecules 11 bbetween the common electrode 17 and the pixel electrode 30 arehorizontally arranged due to the horizontal electric field “L”. Sincethe liquid crystal molecules are arranged by the horizontal electricfield, the IPS mode LCD device has a characteristic of a wide viewingangle. FIG. 2B shows a condition when the voltage is not applied to theIPS mode LCD device. Because an electric field is not generated betweenthe common and pixel electrodes 17 and 30, the arrangement of liquidcrystal molecules 11 is not changed.

In the FFS mode LCD device, one of the pixel electrode and the commonelectrode has a plate shape in the pixel region, and the other one ofthe pixel electrode and the common electrode has an opening. The pixeland common electrode are formed on a lower substrate. As a result,liquid crystal molecules are driven by a fringe field between the pixeland common electrodes.

Unfortunately, since there is no the common electrode, which is formedof a conductive material, on an upper substrate in the IPS mode LCDdevice or the FFS mode LCD device, an anti-static layer, which is formedof a transparent conductive material such as indium-tin-oxide (ITO) andindium-zinc-oxide (IZO), is required on an outer side of the uppersubstrate to prevent problems resulting from a static electricity.Generally, the anti-static layer has a thickness of about 200 angstroms(Å) and a sheet resistance of about 500 ohms per square (Ω/sq). Sincethe sheet resistance of the anti-static layer is substantially same asthat of a metallic material, there is no damage on the device from thestatic electricity due to the anti-static layer.

The IPS mode LCD device or the FFS mode LCD device are used for atelevision, a projector, a mobile phone, a PDA, and so on. Recently,mobile devices include a touch sensor such that the device can beoperated by touching.

Unfortunately, even if a capacitive overlay type touch sensor isincluded in the cell of the IPS mode LCD device or the FFS mode LCDdevice, a change of capacitance generated by a touch can not be detectedbecause of the anti-static layer, which is formed of the transparentconductive material such as indium-tin-oxide (ITO) and indium-zinc-oxide(IZO), of the IPS mode LCD device or the FFS mode LCD device. Namely,the related art IPS mode LCD device or the FFS mode LCD device can notbe operated by a touch sensor.

In more detail, when the user touches his finger onto the IPS mode LCDdevice or the FFS mode LCD device, the capacitance is generated betweenthe finger and the anti-static layer of the IPS mode LCD device or theFFS mode LCD device. The capacitance is discharged into an outer spacethrough the anti-static layer such that the touch of the user can not bedetected by the capacitive overlay type touch sensor. If the anti-staticlayer is removed for the touch sensing, there are damages by the staticelectricity.

SUMMARY OF THE INVENTION

Accordingly, the present invention is directed to a touch sensing typeLCD device and a method of fabrication the same that substantiallyobviates one or more of the problems due to limitations anddisadvantages of the related art.

Additional features and advantages of the invention will be set forth inthe description which follows, and in part will be apparent from thedescription, or may be learned by practice of the invention. Theobjectives and other advantages of the invention will be realized andattained by the structure particularly pointed out in the writtendescription and claims hereof as well as the appended drawings.

To achieve these and other advantages and in accordance with the purposeof the present invention, as embodied and broadly described herein, atouch sensing type liquid crystal display device includes an arraysubstrate including a first substrate, a common electrode, a pixelelectrode, and a touch sensing unit; a color filter substrate includinga second substrate and facing the array substrate; an anti-static layeron an outer side of the second substrate and including an organicmaterial and a carbon nano-tube; and a liquid crystal layer between thefirst substrate and an inner side of the second substrate.

In another aspect of the present invention, a method of fabricating atouch sensing type liquid crystal display device includes forming a gateline, a data line, a thin film transistor, a common electrode, a pixelelectrode and a touch sensing unit on a first substrate; forming ananti-static layer on an outer side of a second substrate, theanti-static layer including an organic material and a carbon nano-tube;and attaching the first and second substrates with a liquid crystallayer interposed between the first and second substrates.

In another aspect of the present invention, a method of fabricating atouch sensing type liquid crystal display device includes forming a gateline, a data line, a thin film transistor, a common electrode, a pixelelectrode and a touch sensing unit on a first substrate; attaching asecond substrate to the first substrate to form a liquid crystal panel,wherein the liquid crystal panel has a first thickness; etching an outerside of each of the first and second substrates such that the liquidcrystal panel has a second thickness smaller than the first thickness;and forming an anti-static layer on the outer side of the secondsubstrate, the anti-static layer including an organic material and acarbon nano-tube.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory and areintended to provide further explanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this specification, illustrate embodiments of the invention andtogether with the description serve to explain the principles of theinvention.

FIG. 1 is a cross-sectional view of an IPS mode LCD device according tothe related art.

FIGS. 2A and 2B are cross-sectional views showing turned on/offconditions of an IPS mode LCD device according to the related art.

FIG. 3 is a schematic plane-view of an array substrate for a touchsensing type LCD device according to the present invention.

FIG. 4 is a plane-view showing a part of an array substrate for a touchsensing type LCD device according to the present invention.

FIG. 5 is a cross-sectional view taken along the line V-V of FIG. 4 .

FIG. 6 is a cross-sectional view taken along the line VI-VI of FIG. 4 .

FIGS. 7A to 7E are cross-sectional view showing a fabricating process ofa touch sensing type LCD device according to an embodiment of thepresent invention.

FIGS. 8A to 8F are cross-sectional view showing a fabricating process ofa touch sensing type LCD device according to an embodiment of thepresent invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will now be made in detail to the preferred embodiments,examples of which are illustrated in the accompanying drawings.

FIG. 3 is a schematic plane-view of an array substrate for a touchsensing type LCD device according to the present invention.

As shown in FIG. 3 , a plurality of touch blocks TB are defined on anarray substrate. In addition, first to third regions A1, A2 and A3 aredefined in each touch block TB. The second region A2 is disposed betweenthe first and third regions A1 and A3. The touch block TB is a unitregion of touch sensing. A plurality of pixel regions P are defined ineach of the first to third regions A1, A2 and A3.

A plurality of gate lines 119 extends along a first direction, i.e., anX direction, and a plurality of data lines 130 extends along a seconddirection, i.e., a Y direction. The gate lines 119 and the data lines130 cross each other to define the pixel regions P.

In addition, an X direction sensing line Xsl extends along the firstdirection through the first region A1 and the third region A3. The Xdirection sensing line Xsl is disposed over the gate line 119. Namely,the X direction sensing line Xsl overlaps the gate line 119. The Xdirection sensing lines Xsl in the first and third regions A1 and A3 inone touch block TB is electrically connected to a connection line 152 inthe second region A2. The connection line 152 extends along the gateline 119 and is spaced apart from the gate line 119 to avoid anelectrical short. The connection line 152 may be formed of the samematerial and disposed at the same layer as the gate line 119. One end ofthe connection line 152 is connected to the X direction sensing line Xslin the first region A1 through a first connection pattern 162, and theother end of the connection line 152 is connected to the X directionsensing line Xsl in the third region A3 through a second connectionpattern 164.

A Y direction sensing line Ysl extends along the second directionthrough the second region A2. The Y direction sensing line Ysl isdisposed over the data line 130. Namely, the Y direction sensing lineYsl overlaps the data line 130. Since the Y direction sensing line Yslis disposed at a different layer than the connection line 152, there isno electrical short.

Although not shown, a common electrode having a plate shape and a pixelelectrode having an opening are formed with an insulating layertherebetween. The pixel electrode in one pixel region is separated fromthat in another pixel region. The common electrode in one touch block TBis separated from that in another touch block TB. In addition, thecommon electrodes the first to third areas A1, A2 and A3 are separatedfrom one another. An X direction sensing circuit is disposed at one endof the X direction sensing line Xsl, and a Y direction sensing circuitis disposed at one end of the Y direction sensing line Ysl. The Xdirection sensing circuit and the Y direction sensing circuit arepositioned at a non-display area at periphery of a display areaincluding the touch blocks TB.

When one touch block TB is touched, a change of capacitance between thepixel and common electrode are detected by the X direction sensingcircuit and the Y direction sensing circuit through the X directionsending line Xsl and the Y direction sensing line Ysl, respectively. Asa result, a position of the touched touch block TB is sensed.

FIG. 4 is a plane-view showing a part of an array substrate for a touchsensing type LCD device according to the present invention. FIG. 5 is across-sectional view taken along the line V-V of FIG. 4 , and FIG. 6 isa cross-sectional view taken along the line VI-VI of FIG. 4 . FIG. 4shows first to third regions each including one pixel region. However,as shown in FIG. 3 , each of the first to third regions may have atleast one pixel region.

As shown in FIGS. 4 to 6 , a gate line 119 and a data line 130 areformed on a first substrate 101. The gate and data lines 119 and 130cross each other to define first to third pixel regions P1, P2 and P3.The first to third pixel regions P1, P2, P3 are respectively included tothe first to third regions A1, A2 and A3.

In each pixel region P, a thin film transistor (TFT) Tr including asemiconductor layer 113, a gate electrode 120, a source electrode 133and a drain electrode 136 is formed. The gate electrode 120 and thesource electrode 133 respectively extend from the gate line 119 and thedata line 130 such that the TFT Tr is electrically connected to the gateline 119 and the data line 130.

The semiconductor layer 113 is formed of polycrystalline silicon. Afirst semiconductor region 113 a of a center of the semiconductor layer113, which is formed of intrinsic polycrystalline silicon, serves as achannel, and second semiconductor regions 113 b at both sides of thefirst semiconductor region 113 a are doped by high-concentrationimpurities. A gate insulating layer 116 is formed on the semiconductorlayer 113.

The gate electrode 120 is formed on the gate insulating layer 116 andcorresponding to the first semiconductor region 113 a. The gate line 119is formed on the gate insulating layer 116 and connected to the gateelectrode 120. A connection line 152 is also formed on the gateinsulating layer 116 and parallel to the gate line 119. The connectionline 152 is spaced apart from the gate line. The connection line 152 isdisposed in the second pixel region P2 of the second region A2, and bothends of the connection line 152 are respectively disposed in the firstpixel region P1 of the first region A1 and the third pixel region P3 ofthe third region A3.

An interlayer insulating layer 123 is formed on the gate line 119, thegate electrode 120 and the connection line 152. For example, theinterlayer insulating layer 123 may be formed of an inorganic insulatingmaterial, for example, silicon oxide or silicon nitride. The interlayerinsulating layer 123 and the gate insulating layer 116 are patterned toform semiconductor contact holes 125 exposing the second semiconductorregions 113 b of the semiconductor layer 113.

On the interlayer insulating layer 123, the data line 130 is formed tocross the gate line 119. In addition, the source electrode 133 and thedrain electrode 136 are formed on the interlayer insulating layer 123.The source and drain electrodes 133 and 136 respectively contact thesecond semiconductor regions 113 b through the semiconductor contactholes 125.

As mentioned above, the semiconductor layer 113, the gate insulatinglayer 116, the gate electrode 120, the interlayer insulating layer 123,the source electrode 133 and the drain electrode 136 constitute the TFTTr. This may be referred to as a top gate type TFT. Alternatively, abottom gate type TFT, where a semiconductor layer is positioned betweena gate electrode as a lower layer of the TFT and source and drainelectrodes as a upper layer of the TFT, may be used.

A first passivation layer 140, which is formed of an inorganicinsulating material, for example, silicon oxide or silicon nitride, anda second passivation layer 145, which is formed of an organic insulatingmaterial, for example, photo-acryl or benzocyclobutene (BCB), arestacked on the data line 130, the source electrode 133 and the drainelectrode 136. The second passivation layer 145 may have a thicknessabout 2 to 4 micrometers to provide a flat top surface. Since anadhesive strength between a metallic material of the data line 130 andthe organic insulating material of the second passivation layer 145 issmaller than an adhesive strength between a metallic material of thedata line 130 and the inorganic insulating material of the firstpassivation layer 140 and between the inorganic insulating material ofthe first passivation layer 140 and the organic insulating material ofthe second passivation layer 145, an adhesive property between themetallic material of the data line 130 and the organic insulatingmaterial of the second passivation layer 145 is improved due to thefirst passivation layer 140. The first passivation layer 140 may beomitted.

A common electrode 150, which has an island shape in each of the firstto third regions A1, A2 and A3, is formed on the second passivationlayer 145. Namely, the common electrode 150 in the second region A2 isseparated from that in each of the first and third regions A1 and A3.The common electrode 150 has a plate shape. The common electrode 150 isformed of a transparent conductive material, for example,indium-tin-oxide (ITO) or indium-zinc-oxide (IZO).

An X direction sensing line Xsl and a Y direction sensing line Ysl areformed on the common electrode 150. The X direction sensing line Xsloverlaps the gate line 119 in the first and third regions A1 and A3, andthe Y direction sensing line Ysl overlaps the data line 130 in thesecond region A2. The Y direction sensing line Ysl extends along thedata line 130 such that the second regions A2 arranged along the dataline 130 are electrically connected by the Y direction sensing line Ysl.The X direction sensing lines Xsl in the first and third regions A1 andA2 of each touch block TB (of FIG. 3 ) are electrically connected toeach other through the connection line 152.

A third passivation layer 155 is formed on the X direction sensing lineXsl and the Y direction sensing line Ysl. The third passivation layer155 may be formed of an inorganic insulating material, for example,silicon oxide or silicon nitride.

The first to third passivation layers 140, 145 and 155 are patterned toform a drain contact hole 157 exposing the drain electrode 136. Inaddition, the third passivation layer 155 is patterned to form first andsecond contact holes 158 a and 159 a respectively exposing the X sensinglines Xsl in the first and third regions A1 and A3. Furthermore, thefirst to third passivation layer 140, 145 and 155 and the interlayerinsulating layer 123 are patterned to form third and fourth contactholes 158 b and 159 b respectively exposing ends of the connection line152.

A pixel electrode 160 is formed on the third passivation layer 155. Thepixel electrode 160 is disposed in each pixel region P and contacts thedrain electrode 136 through the drain contact hole 157. The pixelelectrode 160 is formed of a transparent conductive material, forexample, ITO or IZO. The pixel electrode 160 has at least one openingop, which corresponds to the common electrode 150, such that a fringefield is generated between the pixel and common electrodes 160 and 150.The third passivation layer 155 is interposed between the pixel andcommon electrodes 160 and 150 such that a storage capacitor is formed.

In addition, first and second connection patterns 162 and 164 are formedon the third passivation layer 155. One end of the first connectionpattern 162 contacts the X direction sensing line Xsl in the firstregion A1 through the first contact hole 158 a, and the other end of thefirst connection pattern 162 contacts the connection line 152 throughthe third contact hole 158 b. One end of the second connection pattern164 contacts the X direction sensing line Xsl in the third region A3through the second contact hole 159 a, and the other end of the secondconnection pattern 164 contacts the connection line 152 through thefourth contact hole 159 b. As a result, the X direction sensing line Xslin the first region A1 is electrically connected to the X directionsensing line Xsl in the third region A3.

A second substrate 171 faces the first substrate 101. A black matrix 173is formed on an inner side of the second substrate 171. The black matrix173 corresponds to boundaries of the pixel region P and has a latticeshape. The black matrix 173 may further correspond to the TFT Tr. Acolor filter 175 is formed on the inner side of the second substrate 171and corresponds to the pixel region P. The color filter 175 may includered, green and blue color filters.

In addition, an anti-static layer 180 is formed on an outer side of thesecond substrate 171. The anti-static layer 180 includes a base layer181 of an organic material and a carbon nano-tube 183 in the base layer181. The carbon nano-tube 183 has a conductive property. The anti-staticlayer 180 has a sheet resistance of about 10⁶ to 10⁹ ohms per square(Ω/sq). For example, the organic material for the base layer 181 mayinclude polymethyl methacrylate (PMMA) or polyethylene terephthalate(PET) such that a sheet resistance of the base layer 181 has a rangewithin about 10¹⁴ to 10²⁰ ohms per square (Ω/sq). When only the baselayer 181 is formed on the outer side of the second substrate 171, thebase layer 181 can not serves as an anti-static layer because the sheetresistance of the base layer 181 is too high. Accordingly, there arestrong damages on the device by a static electricity.

However, since the carbon nano-tube 183 is formed with the base layer181 on the outer side of the second substrate 171, the layer 180 has ananti-static property. Namely, since the anti-static layer 180 has asheet resistance of about 10⁶ to 10⁹ ohms per square (Ω/sq), there is nodamage on the device from a static electricity.

By providing a liquid crystal layer 190 between the first and secondsubstrates 101 and 171 and a seal pattern (not shown) at edges of one ofthe first and second substrates 101 and 171, the touch sensing type FFSmode LCD device is obtained. An FFS mode LCD device, which includes thecommon electrode having a plate shape and the pixel electrode having anopening, is show by FIGS. 3 to 6 . Alternatively, an IPS mode LCDdevice, which includes the common and pixel electrodes being alternatelyarranged with each other, is also available.

As mentioned above, the touch sensing type LCD device includes theanti-static layer 180, which includes the base layer 181 and the carbonnano-tube to have a sheet resistance of about 10⁶ to 10⁹ ohms per square(Ω/sq), at an outer side of the second substrate 171. The anti-staticlayer 180 serves as a path for a static electricity and does not serveas an obstructer for touch sensing. Namely, the anti-static layer 180serves as a dielectric layer between a finger and the common electrode150 when the device is touched such that a capacitor is formed betweenthe finger and the common electrode 150. As a result, a touch isdetected by a change of capacitance between the finger and the commonelectrode 150.

In more detail, when one touch block TB (of FIG. 3 ) is touched, theanti-static layer 180, which has a sheet resistance of about 10⁶ to 10⁹ohms per square (Ω/sq), serves as a dielectric layer such that acapacitor is generated by the finger, the common electrode 150, theliquid crystal layer 190, the color filter layer 175, the secondsubstrate 171, the anti-static layer 180, and so on. A change ofcapacitance of the capacitor is detected by the X direction sensingcircuit (not shown) and the Y direction sensing circuit (not shown)through the X direction sensing line Xsl and the Y direction sensingline Ysl, which are respectively connected to the common electrode 150,such that a position of the touched touch block TB is sensed.

Since the static electricity has a voltage of several thousands toseveral hundreds of thousands, the anti-static layer 180, which has asheet resistance of about 10⁶ to 10⁹ ohms per square (Ω/sq), serves as aconductive path for the static electricity. However, since an electriccurrent of the finger has a range within several nano-amperes to severalmicro-amperes, the anti-static layer 180, which has a sheet resistanceof about 10⁶ to 10⁹ ohms per square (Ω/sq), serves as an insulatinglayer for the touch. Accordingly, the anti-static layer 180 serves as adielectric layer of the capacitor for the touch. As a result, the deviceaccording to the present invention including a touch sensing part, i.e.,the X direction sensing line Xsl and the Y direction sensing line Ysl,and the anti-static layer 180 can be operated by a touch sensing, andthere is no damage from a static electricity.

FIGS. 7A to 7E are cross-sectional view showing a fabricating process ofa touch sensing type LCD device according to an embodiment of thepresent invention.

As shown in FIG. 7A, an array substrate is formed by followingprocesses. An intrinsic amorphous silicon layer (not shown) is formed onthe first substrate 101 by depositing intrinsic amorphous silicon. Theamorphous silicon layer is crystallized by irradiating a laser beam orheating to form a polycrystalline silicon layer (not shown). Thepolycrystalline silicon layer is patterned by a mask process to form thesemiconductor layer 113 in each pixel regions P1, P2 and P3. FIGS. 7A to7E show the second pixel region P2 of the second region A2 (of FIG. 3 )in one touch block TB.

Next, the gate insulating layer 116 is formed on the semiconductor layer113 by depositing an inorganic insulating material such as silicon oxideand silicon nitride.

Next, a first metal layer (not shown) is formed on the gate insulatinglayer 116 by depositing one of aluminum (Al), Al alloy (AlNd), copper(Cu), Cu alloy and chromium (Cr). The first metal layer is patterned toform the gate electrode 120, the gate line 119 (of FIG. 4 ) and theconnection line 152 (of FIG. 4 ). The gate electrode 120 corresponds toa center of the semiconductor layer 113 and extends from the gate line119. The connection line 152 is spaced apart from and parallel to thegate line 119. The connection line 152 is disposed in the second regionA2, and both ends of the connection line 152 protrude to the first andthird regions A1 and A3 (of FIG. 3 or FIG. 4 ).

Next, impurities are doped into the semiconductor layer 113 using thegate electrode 120 as a blocking such that the impurities are doped intoboth sides of the semiconductor layer 113. As a result, a firstsemiconductor region 113 a of a center of the semiconductor layer 113,which is formed of intrinsic polycrystalline silicon, serves as achannel, and second semiconductor regions 113 b at both sides of thefirst semiconductor region 113 a are doped by high-concentrationimpurities.

Next, the interlayer insulating layer 123 is formed on the gate line119, the gate electrode 120 and the connection line 152 by depositing aninorganic insulating material, for example, silicon oxide or siliconnitride. The interlayer insulating layer 123 and the gate insulatinglayer 116 are patterned to form the semiconductor contact holes 125exposing the second semiconductor regions 113 b of the semiconductorlayer 113.

Next, a second metal layer (not shown) is formed on the interlayerinsulating layer 123 by depositing one of aluminum (Al), Al alloy(AlNd), copper (Cu), Cu alloy, chromium (Cr), and molybdenum (Mo). Thesecond metal layer is patterned to form the data line 130, the sourceelectrode 133 and the drain electrode 136. The source and drainelectrodes 133 and 136 respectively contact the second semiconductorregions 113 b through the semiconductor contact holes 125. The drainelectrode 136 is spaced apart from the source electrode 133. The dataline 130 extends from the source electrode 133 and crosses the gate line119 to define the pixel regions P1, P2 and P3.

The semiconductor layer 113, the gate insulating layer 116, the gateelectrode 120, the interlayer insulating layer 123, the source electrode133 and the drain electrode 136 constitute the TFT Tr. This may bereferred to as a top gate type TFT. Alternatively, a bottom gate typeTFT, where a semiconductor layer is positioned between a gate electrodeas a lower layer of the TFT and source and drain electrodes as a upperlayer of the TFT, may be used. To form the bottom gate type TFT, a stepof forming the gate electrode, the gate line and the connection line, astep of forming the gate insulating layer, a step of forming asemiconductor layer, which includes an active layer of intrinsicamorphous silicon and an ohmic contact layer of impurity-doped amorphoussilicon, and a step of forming the data line, the source electrode andthe drain electrode are sequentially processed.

Next, a first passivation layer 140 and a second passivation layer 145are sequentially formed on the TFT Tr and the data line 130 bydepositing an inorganic insulating material and coating an organicinsulating material. The second passivation layer 145 has a flat topsurface. The first passivation layer 140 for enhancing an adhesiveproperty between a metallic material of the data line and the organicinsulating material of the second passivation layer 145 may be omitted.

Next, a first transparent conductive material layer (not shown) isformed on the second passivation layer 145 by depositing a transparentconductive material, for example, ITO or IZO. The first transparentconductive material layer is patterned to form the common electrode 150.As mentioned above, the common electrode 150 has an island shape in eachof the first to third regions A1, A2 and A3. Namely, the commonelectrode 150 in the second region A2 is separated from that in each ofthe first and third regions A1 and A3.

Next, a third metal layer (not shown) is formed on the common electrode150 by depositing one of aluminum (A1), A1 alloy (AlNd), copper (Cu) andCu alloy. The third metal layer is patterned to form the X directionsensing line Xsl (of FIG. 4 ) and the Y direction sensing line Ysl. TheX direction sensing line Xsl overlaps the gate line 119 in the first andthird regions A1 and A3, and the Y direction sensing line Ysl overlapsthe data line 130 in the second region A2. The Y direction sensing lineYsl extends along the data line 130 such that the second regions A2arranged along the data line 130 are electrically connected by the Ydirection sensing line Ysl. The X direction sensing lines Xsl in thefirst and third regions A1 and A2 of each touch block TB (of FIG. 3 )are electrically connected to each other through the connection line152.

Next, a third passivation layer 155 is formed on the X direction sensingline Xsl and the Y direction sensing line by depositing an inorganicinsulating material, for example, silicon oxide or silicon nitride. Thethird passivation layer 155 is patterned to form first and secondcontact holes 158 a and 159 a respectively exposing the X sensing linesXsl in the first and third regions A1 and A3. The first to thirdpassivation layers 140, 145 and 155 are patterned to form a draincontact hole 157 exposing the drain electrode 136. The first to thirdpassivation layer 140, 145 and 155 and the interlayer insulating layer123 are patterned to form third and fourth contact holes 158 b and 159 brespectively exposing ends of the connection line 152.

Next, a second transparent conductive material layer (not shown) isformed on the third passivation layer 145 by depositing a transparentconductive material, for example, ITO or IZO. The second transparentconductive material layer is patterned to form the pixel electrode 160,and the first and second connection patterns 162 and 164. The pixelelectrode 160 is disposed in each pixel region P and contacts the drainelectrode 136 through the drain contact hole 157. The pixel electrode160 has at least one opening op, which corresponds to the commonelectrode 150, such that a fringe field is generated between the pixeland common electrodes 160 and 150. One end of the first connectionpattern 162 contacts the X direction sensing line Xsl in the firstregion A1 through the first contact hole 158 a, and the other end of thefirst connection pattern 162 contacts the connection line 152 throughthe third contact hole 158 b. One end of the second connection pattern164 contacts the X direction sensing line Xsl in the third region A3through the second contact hole 159 a, and the other end of the secondconnection pattern 164 contacts the connection line 152 through thefourth contact hole 159 b. As a result, the X direction sensing line Xslin the first region A1 is electrically connected to the X directionsensing line Xsl in the third region A3.

Next, as shown in FIG. 7B, a liquid phase organic mixture including asolution, which includes an organic material such as PMMA and PET withan organic solvent, and a carbon nano-tube is coated on an outer side ofthe second substrate 171 under a room temperature by a spin coatingapparatus (not shown) or a slit coating apparatus (not shown) to form anorganic solution layer 182. The organic material is inserted into theorganic solvent to form the solution, and the power-type carbonnano-tube is inserted into the solution. The resulting solution is mixedto form liquid phase organic mixture.

Next, as shown in FIG. 7C, the organic solution layer 182 (of FIG. 7C)including the carbon nano-tube is dried by heating in a furnace or oven197 to volatilize and remove the organic solvent. As a result, theanti-static layer 180 including the base layer 181 of the organicmaterial and the carbon nano-tube 183 is formed on the outer side of thesecond substrate 171. As mentioned above, the anti-static layer 180 hasa sheet resistance of about 10⁶ to 10⁹ ohms per square (Ω/sq). Forexample, the anti-static layer 180 has a thickness of about 300 to 1000angstroms. The sheet resistance of the anti-static layer 180 iscontrolled depending on a relative weight % of the carbon nano-tube withrespect to the organic material.

Next, as shown in FIG. 7D, a light blocking material, for example, ablack resin, is coated on an inner side of the second substrate 171 andpatterned by a mask process to form the black matrix 173. Next, thecolor filter 175 including the red, green and blue color filters isformed on the inner side of the second substrate 171. As a result, acolor filter substrate is obtained. Although not shown, an overcoatlayer for providing a flat top surface may be formed.

Next, as shown in FIG. 7E, the array substrate and the color filtersubstrate are disposed such that the color filter layer 175 faces thepixel electrode 160, and a seal pattern (not shown) is formed alongedges of one of the array substrate and the color filter substrate.Next, the liquid crystal layer 190 is disposed between the arraysubstrate and the color filter substrate, and the array substrate andthe color filter substrate are attached to form a liquid crystal panel.

Although not shown, the X direction sensing circuit and the Y directionsensing circuit, which are respectively connected to the X directionsensing line and the Y direction sensing line, and a driving circuitconnected to the gate line 119 and the data line 130 are formed on theliquid crystal panel to obtain the device 100.

FIGS. 8A to 8F are cross-sectional view showing a fabricating process ofa touch sensing type LCD device according to an embodiment of thepresent invention.

The process shown by FIGS. 8A to 8F has difference in a step of formingthe anti-static layer and a step of etching the first and secondsubstrates. Accordingly, below explanation is focused on thedifferences.

As shown in FIG. 8A, the array substrate is obtained by forming the TFTTr, the gate line 119, the data line 130, the X direction sensing lineXsl, the Y direction sensing line Ysl, the common electrode 150, thepixel electrode 160, the connection line 152, the connection patterns162 and 164, and so on.

Next, as shown in FIG. 8B, the black matrix 173 and the color filterlayer 175 are formed on an inner side of the second substrate 171.

Next, as shown in FIG. 8C, the first substrate 101 and the secondsubstrate 171 are disposed such that the color filter layer 175 facesthe pixel electrode 160, and a seal pattern (not shown) is formed alongedges of one of the first substrate 101 and the second substrate 171.Next, the liquid crystal layer 190 is disposed between the firstsubstrate 101 and the second substrate 171, and first substrate 101 andthe second substrate 171 are attached to form a liquid crystal panel.

Next, as shown in FIG. 8D, the liquid crystal panel is exposed to anetchant, which is capable of etching glass of the first and secondsubstrates 101 and 171, to reduce a thickness of each of the first andsecond substrates 101 and 171. Namely, a thickness of liquid crystalpanel is reduced. For example, the etchant may include hydrofluoric acid(HF). A dipping process or a spray process may be used. As a result,light weight and thin profile LCD device can be obtained.

When the thickness of the first and second substrates 101 and 171 arereduced before forming elements, for example, the TFT Tr or the colorfilter layer 175, there may be crack or brokenness. Accordingly, asmentioned above, after forming the elements on the first and secondsubstrates 101 and 171, the etching process is performed to reduce thethickness of the first and second substrates 101 and 171. For example,the first and second substrates 101 and 171 may have a thickness ofabout 0.2 to 0.3 mm after the etching process.

Next, as shown in FIG. 8E, a liquid phase organic mixture including asolution, which includes an organic material such as PMMA and PET withan organic solvent and a carbon nano-tube is coated on an outer side ofthe second substrate 171, which having a reduced thickness, under a roomtemperature by a spin coating apparatus (not shown) or a slit coatingapparatus (not shown) to form an organic solution layer 182. The organicmaterial is inserted into the organic solvent to form the solution, andthe power-type carbon nano-tube is inserted into the solution. Theresulting solution is mixed to form liquid phase organic mixture.

Next, as shown in FIG. 8F, the organic solution layer 182 (of FIG. 8E)including the carbon nano-tube is dried by heating in a furnace or oven(not shown) to volatilize the organic solvent. As a result, theanti-static layer 180 including the base layer 181 of the organicmaterial and the carbon nano-tube 183 is formed on the outer side of thesecond substrate 171. As mentioned above, the anti-static layer 180 hasa sheet resistance of about 10⁶ to 10⁹ ohms per square (Ω/sq). Forexample, the anti-static layer 180 has a thickness of 300 to 1000angstroms. The drying process may be performed under a temperature of100° C., beneficially a temperature between about 50 to 80° C., toprevent a damage to the seal pattern by expansion of the liquid crystallayer 190 and a change of phase of the liquid crystal layer 190.

Although not shown, the X direction sensing circuit and the Y directionsensing circuit, which are respectively connected to the X directionsensing line and the Y direction sensing line, and a driving circuitconnected to the gate line 119 and the data line 130 are formed on theliquid crystal panel to obtain the device 100.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the present inventionwithout departing from the spirit or scope of the invention. Thus, it isintended that the present invention cover the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

What is claimed is:
 1. A display device, comprising: a first substrateand a second substrate facing each other; a plurality of firstelectrodes and a plurality of second electrodes disposed between thefirst substrate and the second substrate; a third electrode disposed onat least one of the first substrate and the second substrate; and aplurality of first conductive lines and a plurality of second conductivelines, one of the plurality of second conductive lines beingelectrically connected to one of the plurality of second electrodes,wherein the third electrode overlaps the plurality of first electrodesand the plurality of second electrodes in a plan view, wherein a sheetresistance of the third electrode is greater than a sheet resistance ofthe plurality of first electrodes and the plurality of secondelectrodes, and wherein the one of the plurality of second conductivelines directly contacts the one of the plurality of second electrodes.2. The display device according to claim 1, wherein the plurality ofsecond conductive lines extend along the plurality of first conductivelines.
 3. The display device according to claim 2, wherein the firstconductive lines are data lines.
 4. The display device according toclaim 3, wherein the one of the plurality of second conductive linesextends along one of the data lines and overlaps the one of the datalines.
 5. The display device according to claim 1, wherein a minimumdistance between the plurality of first electrodes and the plurality ofsecond electrodes is less than a minimum distance between the thirdelectrode and the plurality of second electrodes.
 6. The display deviceaccording to claim 1, wherein the plurality of second electrodes includea plurality of first sub-electrodes and a plurality of secondsub-electrodes, and wherein the display panel is configured to be drivenby a voltage of the plurality of first electrodes and the plurality offirst sub-electrodes.
 7. The display device according to claim 6,wherein the plurality of first sub-electrodes is separated from theplurality of second sub-electrodes.
 8. The display device according toclaim 1, wherein the third electrode serves as a conductive path forstatic electricity or an insulating layer for sensing a touch position.9. The display device according to claim 1, wherein the sheet resistanceof the third electrode has a range of about 10⁶ to 10⁹ ohms per square(Ω/sq).
 10. The display device according to claim 1, further comprising:a liquid crystal layer between the first and second substrates, whereinthe plurality of first electrodes, the plurality of second electrodes,the plurality of first conductive lines, and the plurality of secondconductive lines are disposed on the first substrate.
 11. The displaydevice according to claim 10, wherein the third electrode is disposed onan outer side of the second substrate.
 12. The display device accordingto claim 1, wherein the plurality of first electrodes are disposedbetween the plurality of second electrodes and the third electrode. 13.The display device according to claim 1, wherein the one of theplurality of second conductive lines is disposed on the one of theplurality of second electrodes.
 14. The display device according toclaim 1, further comprising: a plurality of third conductive linesextending along a direction different from a direction of the firstconductive lines; and a thin film transistor including a semiconductorlayer, a gate electrode, a source electrode, and a drain electrode,wherein one of the first conductive lines is electrically connected tothe source electrode, and one of the third conductive lines iselectrically connected to the gate electrode.
 15. A display device,comprising: a first substrate and a second substrate facing each other;a plurality of first electrodes and a plurality of second electrodesdisposed between the first substrate and the second substrate; a thirdelectrode disposed on at least one of the first substrate and the secondsubstrate; and a plurality of first conductive lines and a plurality ofsecond conductive lines, one of the plurality of second conductive linesbeing electrically connected to one of the plurality of secondelectrodes, wherein the third electrode overlaps the plurality of firstelectrodes and the plurality of second electrodes in a plan view,wherein a sheet resistance of the third electrode is greater than asheet resistance of the plurality of first electrodes and the pluralityof second electrodes, wherein the plurality of second electrodes includea plurality of first sub-electrodes and a plurality of secondsub-electrodes, wherein the display panel is configured to be driven bya voltage of the plurality of first electrodes and the plurality offirst sub-electrodes, and wherein the plurality of first sub-electrodesgroup into a first touch block defining a first unit region for touchsensing, and the first touch block overlaps with at least one of theplurality of second conductive lines.
 16. The display device accordingto claim 15, wherein the plurality of second sub-electrodes group into asecond touch block defining a second unit region for touch sensing. 17.The display device according to claim 16, wherein the first touch blockis separated from the second touch block.
 18. The display deviceaccording to claim 15, wherein the plurality of first sub-electrodes arearranged along the plurality of first conductive lines and areelectrically connected by at least one of the plurality of secondconductive lines.
 19. The display device according to claim 15, whereinthe first touch block includes a plurality of pixel regions.